28620639 has 24 divisors (see below), whose sum is σ = 43993872. Its totient is φ = 17867520.

The previous prime is 28620637. The next prime is 28620643. The reversal of 28620639 is 93602682.

28620639 is a `hidden beast` number, since 28 + 620 + 6 + 3 + 9 = 666.

It is not a de Polignac number, because 28620639 - 2¹ = 28620637 is a prime.

It is a super-3 number, since 3×28620639³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28620637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42969 + ... + 43629.

It is an arithmetic number, because the mean of its divisors is an integer number (1833078).

Almost surely, 2^28620639 is an apocalyptic number.

28620639 is a deficient number, since it is larger than the sum of its proper divisors (15373233).

28620639 is a wasteful number, since it uses less digits than its factorization.

28620639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 967 (or 964 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 28620639 is about 5349.8260719392. The cubic root of 28620639 is about 305.8861232038.

The spelling of 28620639 in words is "twenty-eight million, six hundred twenty thousand, six hundred thirty-nine".